Manufacturing electronic circuitry that includes an inductor or a transformer poses several problems with regard to efficiently and reliably providing the inductor or transformer.
U.S. Pat. No. 4,536,733, incorporated herein by reference, discloses a low leakage inductance inverter transformer utilizing a toroidal ferrite core having a primary winding wound thereon, with the secondary winding constructed from stamped conductive clips ranged to encompass portions of the core and primary winding with clip interconnections formed by printed circuit interconnections is described. The conductive clip described includes integral pins for making connection to printed circuit wiring on a printed circuit board. The turns ratio is selected by the pattern of printed circuit interconnection of the conductive clips such that the transformer structure turns ratio is established by the associated printed circuit interconnection pattern.
U.S. Pat. No. 5,461,353, incorporated herein by reference, discloses a multilayer printed circuit board that includes a plurality of layers. Located within intermediate layer is an inductor, which is shielded by top layer ground plane and bottom layer ground plane. In another embodiment, the inductor can have its inductance adjusted by way of an inductance adjustment runner or by an electronic inductance adjustment device. The inductor is formed by interconnecting first metallization patterns located on first surface with second metallization patterns located on second surface of a printed circuit board layer.
JP 2002-075735 discloses an inductor formed by bonding pads arranged in a matrix form on a printed wiring board. Pattern arms form wiring patterns in one direction by connecting bonding pads to each other arranged in that direction. Bonding wires bond arbitrary bonding pads and constitute adjacent wiring patterns. The inductance value of the inductor element can be adjusted, by changing at least one of the lengths of the bonding wires, the lengths of the wiring patterns, and the number of the wiring patterns by selecting desired bonding pads from the bonding pads constituting the wiring patterns.